Yes
Not a thing
There is no 44 gauge gun.
Yes. The Mossberg 500A1 is a .12 gauge shotgun.
.61 Caliber is the same as 20 gauge. Rifles are generally measured in caliber which is expressed as bore diameter. A .44 magnum means a .44 inch bore; similarly countries with the metric system use metric bore measurements (ie. 9mm Luger) Shotgun measurements are expressed in gauges. Gauge measurements are fractions of a 1 pound ball of lead. A one gauge shotgun shoots a one pound ball of lead. A 12 gauge takes 12 round lead balls to equal a pound and a 10 gauge equals a tenth of a pound. The smaller the gauge; the larger the bore. The only shotgun I am aware of that is measured differently is the .410 shotgun which is approximately .45 caliber or a 67.62 gauge.
To determine exact value of a 1904 Marlin 12 gauge pump shotgun, you would actually have to take a number of factors into consideration. The main thing to consider would be the condition of the shotgun.
THE GUN IS A .44 CALIBER SHOTGUN, NOT A .410 CALIBER. I HAVE BEEN TOLD THAT IT MAY HANDLE VERY SHORT .410 CALIBER SHOT SHELLS OF LOW POWER BUT, IT COULD RISKY.
Yes, a 12 gauge shotgun is considered a firearm.
A bolt action shotgun in 12 gauge.
There is no such shotgun gauge.
What is the value oof a .410 gauge shotgun
Standard 16 gauge shotgun shells.